Boost PFC current limit shoudl not be tight?

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cupoftea

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Hi,
Just got a PFC stage in.
The peak current is limited to just 3% above the maximum peak current thats seen at max load, minimum vin.
Do you agree this is too tight?
For PFC, peak current limitation should be to at least approx 10% above atual max peak current?

This is because PFCs have slow feedback loop, and if the sense current limit is too tight, then the PFC will just oscillate, "motor-boating" from
max to minimum output...would you agree?
 

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Also, is it not odd that not all CCM PFC controllers have a separate peak current limit pin, as well as the average current limiting pin(s)?
I have never done PFC without the additional fast current limit......i woudl imagine things can get a bit hairy after transients when there is no fast current limit...maybe these "no fast current limit" PFC chips are for use with IGBTs which can handle high surging currrents better?
 

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